#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;
  vector<int> dp(100 * n + 1);
  int sum = 0;

  dp[0] = 1;
  REP (i, n) {
    int w;
    cin >> w;
    sum += w;
    for (int j = dp.size() - 1; j >= 0; j--)
      if (j >= w)
        dp[j] |= dp[j - w];
  }

  if (sum % 2 == 0 && dp[sum / 2])
    cout << "possible" << endl;
  else
    cout << "impossible" << endl;
  
  return 0;
}